The World Health Organization (WHO) is urging health officials around the world to report any patients presenting with acute respiratory symptoms that could be associated with the newly identified SARS-like virus that has been confirmed in two patients so far.

On Tuesday, the WHO issued a case definition of the disease to help countries identify potential infections. The definition offers criteria for classifying patients as “under investigation,” a “probable case” and a “confirmed case,” based on symptoms, laboratory confirmation of the virus, close contact with someone who could have been infected, or recent travel to Saudi Arabia or Qatar.

The WHO put out a global alert on Sunday when the novel coronavirus — in the same family of viruses that causes common colds as well as SARS — was discovered in a 49-year-old Qatari man who had recently traveled to Saudi Arabia; that patient is currently in isolation and being treated for kidney failure in London. Earlier this year, a Saudi Arabian man died from infection with the same virus, which has led scientists to speculate that the virus may be circulating in the Middle East.

No other cases of the disease have been confirmed so far, but Agence France Presse reports that five people in Denmark (four in the same family) are in isolation in the hospital with flu-like symptoms, fever and coughing. The father of the family was recently in Saudi Arabia, and the unrelated man had traveled to Qatar.

The WHO recommends more monitoring for individuals experiencing severe respiratory symptoms, who have either had close contact with a confirmed or probable case of new-coronavirus infection in the previous 10 days or recently traveled to Qatar or Saudi Arabia. Symptoms of the virus can include a fever of at least 100.4°F (38°C), a cough and respiratory issues requiring hospitalization.

Health experts are still investigating how infectious the new virus is, or whether it could spread as rapidly or become as deadly as SARS, which killed about 800 people in 2003. But so far, officials do not believe the disease is very contagious and that it doesn’t resemble SARS. WHO spokesman Gregory Hartl told reporters, “This is not SARS, it will not become SARS, it is not SARS-like.”

It’s not yet clear what the rate of infection of the novel virus is, or how many cases are severe versus mild. “We don’t know if all cases of infections are as severe as the two cases [present] currently or in fact whether there have been 2 million cases of this virus and only 2 severe cases,” said Hartl.

According to Reuters, Saudi Arabia has said it has taken precautions to prevent spread of the disease during the annual Hajj pilgrimage next month, when the country expects more than two million Muslims to travel to Mecca. The WHO has not recommended any travel restrictions.